Auroral sounds no myth, say scientists

Emma Woollacott, 10th July 2012

The many wilderness travelers who have claimed that the northern lights make sounds have been vindicated at last.

Such accounts had long been discounted by scientists on the grounds that the aurora borealis was simply too far away for anybody to be able to hear anything.

Now, though, researchers at Aalto University in Finland have located the sounds, and found they're formed just 70 meters above ground level. The folk tales, it seems, are correct.

The team installed three separate microphones in an observation site where the aurora borealis was seen, and used them to locate the faint sounds.

"Our research proved that, during the occurrence of the northern lights, people can hear natural auroral sounds related to what they see," says said Professor Unto K. Laine from Aalto University.

"In the past, researchers thought that the aurora borealis was too far away for people to hear the sounds it made. This is true. However, our research proves that the source of the sounds that are associated with the aurora borealis we see is likely caused by the same energetic particles from the sun that create the northern lights far away in the sky."

These particles, or the geomagnetic disturbance produced by them, seem to create sound much closer to the ground.

But it's still unclear just how they do this, especially given that sounds aren't always heard when the northern lights are seen.

And descriptions of the sounds vary widely, with some people reporting brief crackles or muffled bangs, and others decribing distant noise and sputter.

Because of these different descriptions, researchers suspect that there are several mechanisms at play.